The advantages are: firstly, economy. It has many functions, such as bed, carpet, chair or sofa. According to my estimation, the cost of laying "tatami" in a room of the same size is only three to a quarter of that of the western layout. Secondly, space can be used effectively. In the case of a small room, if you don't put a bed or a desk and chair, you will save a lot of space. This is in line with the reality of Japan's small territory. I also read a research report in the newspaper that sitting on tatami for a long time is good for health. Sitting on a soft sofa for a long time will relax the muscles of legs, hips and waist, while the muscles sitting on tatami will be in a state of tension, so there will be no fear of muscle relaxation.